Body cavity-observing apparatus

ABSTRACT

A body cavity-observing apparatus has an endoscope with an imaging optical system on the front edge thereof, a prism movably mounted on the forefront of the imaging optical system, and an actuator to drive the prism on a given command signal. Then, a different endoscope image is obtained by moving the prism, and thus, a wide range endoscope image can be easily obtained.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a body cavity-observing apparatus forobserving an internal organ or the like in the body cavity, including anendoscope with an imaging optical system at the forefront thereof tophotograph an endoscope image.

[0003] 2. Description of the Prior Art

[0004] Generally, endoscopes to be used in body cavities are classifiedas rigid endoscopes or fiberscopes. In order to obtain a differentendoscope image through the movement of an endoscope, it is required ina rigid endoscope that the rigid endoscope itself is moved and it isrequired in a fiberscope that the fiberscope itself is moved or bended.

[0005] Recently, various endoscope manupulators in which endoscopes areinstalled have been developed. The endoscope manupulator can move theendoscope therein rapidly and obtain a different scope effectively.However, since the endoscope manupulator drives the conventionalendoscope only actively, it may degrade the working property because ofthe movement or bending of the endoscope by an operator. Moreover, ifthe endoscope manupulator is operated mistakenly from a mistaken datainput, the forefront of the endoscope may be made an approach to aninternal organ more than necessary.

[0006] In order to iron out the above conventional matters, thepublications of unexamined patent applications Tokukai Hei 8-164148 (JPA8-164148) and Tokukai Hei 10-290777 (JPA 10-290777) disclosescope-moving technique. In the former publication, an endoscope followsa medical tool to obtain various endoscope image data on a wide-angleoptical image, which are recorded in a memory. Then, a desired imagedata is selected from the recorded endoscope image data to control thescope of the endoscope. In the latter publication, all or a part of asuper wide-angle optical image is displayed from a super wide-angle lensprovided at the forefront of an endoscope to control the scope of theendoscope.

[0007] In the former case, since the recorded endoscope image data arebased on the wide-angle optical image, each image data becomes verysmall, resulting in the degradation of the resolution and thus, thedegradation of the endoscope image in quality. In the latter case, ifthe part of the super wide-angle optical image is selected, the selectedoptical image also becomes very small, resulting in the degradation ofthe resolution and thus, the degradation of the endoscope image inquality, as mentioned above. Moreover, since the super wide-angleoptical lens provides more distorted images at the fringes than at thecenter, all of the wide-angle optical image can not be providedpractically.

SUMMERY OF THE INVENTION

[0008] It is an object of the present invention to provide a bodycavity-observing apparatus which can provide various endoscope images ingood quality without the movement or bending of an endoscope.

[0009] Therefore, this invention relates to a body cavity-observingapparatus comprising an endoscope with an imaging optical system on thefront edge thereof, a prism movably mounted on the forefront of theimaging optical system, and an actuator to drive the prism on a givencommand signal, whereby a different endoscope image is obtained throughthe movement of the prism.

[0010] According to the body cavity-observing apparatus of the presentinvention, the different endoscope image can be easily obtained bymoving the prism without the mechanical movement or the mechanicalbending of the endoscope. As a result, a wide range endoscope image canbe easily obtained. Moreover, since only a given area directed by theprism is observed, the resolution of the thus obtained endoscope imagecan be enhanced. Furthermore, for example under a surgical operation,the working property and the safety of not making an approach to aninternal organ more than necessary are improved.

[0011] In a preferred embodiment of the present invention, the prismincludes a first and a second wedged prisms having the same verticalangle which are provided closely and of which their adjacent oppositesurfaces are orthogonal to the optical axis of the wedge prisms, and theactuator includes a first and a second outer tubes which are attachedindependently movably to the first and the second wedge prisms and afirst and a second motors to rotate the first and the second wedgeprisms around the optical axis, respectively. In this case, thedifferent endoscope image can be easily obtained through the independentrotations of the wedge prisms, and thus, the wide range endoscope imagecan be easily obtained.

[0012] In another preferred embodiment of the present invention, theprism includes one wedge prism, and the actuator includes an outer tubemovably provided on the periphery of the endoscope, a joining shaft tojoin the wedge prism and the outer tube, a first motor to tilt the wedgeprism for the optical axis via the joining shaft and a second motor torotate the wedge prism around the optical axis through the rotation ofthe outer tube. In this case, the different endoscope image can beeasily obtained through the rotation and tilt of the one wedge prism,and thus, the wide range endoscope image can be obtained.

[0013] In still another preferred embodiment of the present invention,the prism includes a liquid prism, and the actuator includes a first anda second link mechanisms which adjust the tilt angles for two directionsorthogonal to the optical axis, respectively. The first and the secondlink mechanisms comprises pairs of link shafts composed of planerportions joined with the periphery of the liquid prism and orthogonalportions orthogonally followed by the planer portions, link members tosupport the orthogonal portions of the link shafts, and motors to rotatethe link members. In this case, the different endoscope image can beeasily obtained through the backward and forward movement of the liquidprism, and thus, the wide range endoscope image can be easily obtained.

[0014] Moreover, it is desired that the link members have theirelongated holes, respectively, and the link shafts are moved backwardand forward by slipping the orthogonal portions in the elongated holesthrough the rotation of the link members by the motors.

[0015] In a further preferred embodiment of the present invention, aposition-detecting means to detect the position of the prism isprovided. An endoscope image is calibrated in its color aberration ordistortion on the basis of the prism position information from theposition-detecting means. Therefore, the resolution of the endoscopeimage can be more enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] For better understanding of the present invention, reference ismade to the attached drawings, wherein

[0017]FIG. 1 is a schematic view showing the entire structure of a bodycavity-observing apparatus according to the present invention, FIGS.2(a)-2(c) are explanatory views for the principle of the bending of anoptical axis using a wedge prism in the body cavity-observing apparatusshown in FIG. 1,

[0018]FIG. 3 is a schematic view showing the entire structure of anotherbody cavity-observing apparatus according to the present invention, and

[0019]FIG. 4 is a schematic view showing the entire structure of stillanother body cavity-observing apparatus according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] This invention will be described in detail with reference tofigures.

[0021]FIG. 1 is a schematic view showing the entire structure of a bodycavity-observing apparatus according to the present invention. Thedepicted body cavity-observing apparatus has, as an endoscope, a rigidendoscope 1 having about 10 mm diameter in its part to be inserted andabout 300 mm entire length. Moreover, the endoscope may be constructedof a fiberscope.

[0022] A CCD camera 2 is provided, as an imaging means, in the rightside of FIG. 1. Herein, if a zoom mechanism is added, it is providedbetween the rigid endoscope 1 and the CCD camera 2. Moreover, an imagingoptical system (not shown) to photograph an endoscope image is mountedat the forefront of the rigid endoscope 1 (in the left side of FIG. 1).A first and a second wedge prisms 3 and 4 to constitute a prism meansare attached to the forefront of the imaging optical system movably. Thewedge prisms 3 and 4 have the same wedge vertical angle Ow as shown inFIG. 2(a), and are positioned closely so that their first surfaces 3 aand 4 a perpendicular to the optical axis X are opposed each other asshown in FIG. 2(b).

[0023] The wedge prisms 3, 4 and the rigid endoscope 1 are covereddoubly with a first and a second outer tubes 5 and 6 which areindependently movable. At the right edges of the outer tubes 5 and 6 areattached gears (not shown), to which gears 7 b and 8 b to be joined withthe forefronts of the rotation shafts 7 a and 8 a of a first and asecond motors 7 and 8 are checked. Rotary encoders 9 and 10 to detectthe motor driving amount (rotation number) are joined with the rightedges of the motors 7 and 8. The outer tubes 5, 6 and the motors 7 and 8constitute an actuator to drive the wedge prisms 3 and 4.

[0024] A controller 11 to control the driving amounts of the motors 7and 8 is provided. To the controller 11 are input a command signal froman operating interface 12 controlled by an operator, the driving amountsof the motors 7 and 8 detected by the rotary encoders 9 and 10, and anendoscope image from the CCD camera 2. The controller 11 has a scopecontrolling part 13 to control the driving amounts of the motors 7 and 8based on the command signal from the operating interface 12, and a prismposition-detecting part 14 to detect the movement positions of the wedgeprisms 3 and 4 based on the driving amounts of the motors 7 and 8detected by the rotary encoders 9 and 10.

[0025] Moreover, the controller 11 has a calibration table 16 for coloraberration and distortion, and an image processing part 15 to calibratethe color aberration and distortion of an endoscope image detected bythe CCD camera 2 based on the calibration table 16. In this case, amonitor 17 may be prepared so that the endoscope image can be observed.

[0026] The controller 11, the operating interface 12 and the monitor 17may be constructed of a general-purpose computer, for example. In thiscase, the scope controlling part 13, the prism position-detecting part14 and the image processing part 15 of the controller 11 may beconstructed of a given software installed in the computer, and thecalibration table 16 of the controller 11 may be constructed of the datarecorded in a memory (RAM, ROM, hard disk, etc.) in the computer.Moreover, the operating interface 12 maybe constructed of the key boardor the mouse of the computer. The scope controlling part 13, the prismposition-detecting part 14 and the image processing part 15 may beconstructed of other devices, and the image processing part 15 may bemade of a hardware such as an image processing board.

[0027] The scope controlling operation using the above bodycavity-observing apparatus will be described hereinafter.

[0028] When a command signal to follow an object to be observed inputinto the scope controlling part 13 from the operating interface 12, thedriving amounts of the motors 7 and 8 are determined by the scopecontrolling part 13, to drive the motors 7 and 8 by the determineddriving amounts. Then, the wedge prisms 3 and 4 are rotatedindependently by the motors 7 and 8 in the directions designated by thearrows A and B via the rotation shafts 7 a and 8 a, the gears 7 b and 8b, and the outer tubes 5 and 6. As a result, the prisms 3 and 4 aremoved at their different positions from their starting positions.

[0029] Providing that a light beam is introduced along the optical axisX onto the first surface 4 a of the wedge prism 4 perpendicular to theoptical axis X, the relation between the wedge vertical angle θw of thewedge prism 4 and the light beam polarizing angle θd is represented bythe following equation:

θd=arcsin(nsinθw)−θw  (1)

[0030] Herein, reference character “n” designates the refractive indexof the wedge prism 4.

[0031] Therefore, the endoscope image in the θd direction can beobserved by the wedge prism 4 movably attached at the forefront of therigid endoscope 1. If the wedge prism 4 is rotated around the opticalaxis X of the rigid endoscope 1, the endoscope image within the regionof the θd direction around the optical axis X can be observed.

[0032] Moreover, if the adjacent two wedge prisms 3 and 4 are rotatedindependently in the directions of the arrows A and B around the opticalaxis X, the light beam can be deflected in a given direction within aconical shape defined by the wedge prisms 3 and 4. The maximumdeflection angle is a half of the vertical angle of the conical shape,and is almost defined as 20 d if the vertical angles of the wedge prisms3 and 4 are very small. Therefore, the light beam can be deflectedwithin a region of 40 d by the wedge prisms 3 and 4, as shown in FIG.2(b).

[0033] As a result, in the above body cavity-observing apparatusaccording to the present invention in which the two wedge prisms 3 and 4are provided closely and rotated independently, the deflecting conditionof the light beam from the optical axis X is controlled on the basis ofthe command signal from the operating interface 12, and a differentendoscope image can be obtained within the 40 d region.

[0034] In the observation of the different endoscope image through themovement of the wedge prisms 3 and 4, the observed endoscope image maybe distorted to some degree due to the incident angle of the light beam,the angle of the incident surface of the wedge prisms and the distanceof the light beam from the optical axis X. Moreover, since therefractive indexes n of the wedge prisms are changed on the wavelengthof the light beam, the observed endoscope image has color aberrationtherein. The degrees of the distortion and the color aberration of theendoscope image can be obtained from the calculation or the calibration,depending on the positions of the wedge prisms when they are rotatedaround the optical axis X, and thus, in this embodiment, stored in thecalibration table 16 of the controller 11.

[0035] In the above controller 11, as mentioned above, the rotaryencoders 9 and 10 as position-detecting means detect the driving amountsof the motors 7 and 8, and the positions of the wedge prisms 3 and 4 todefine the endoscope image are measured on the driving amounts. Then,the calibrations for the color aberration and the distortion of theendoscope image related to the positions of the wedge prisms aredetermined from the calibration table 16. Subsequently, the endoscopeimage is calibrated in its color aberration and the distortion by theimage processing part 15 on the measured color aberration calibrationand distortion calibration, and is displayed on the monitor 17. If thecolor aberration or the distortion is very small and negligible, thecalibration for the one may be omitted.

[0036] In the above body cavity-observing apparatus, only if a givencommand signal is input into the operating interface 12, the wedgeprisms 3 and 4 are rotated to their respective positions and thus, adifferent endoscope image can be obtained from the movement of the wedgeprisms 3 and 4. Therefore, under a surgical operation, the workingproperty can be developed and the forefront of the endoscope can not bemade an approach to an internal organ more than necessary.

[0037] Moreover, since only a given area directed by the wedge prisms 13and 14 is observed, the resolution of the endoscope image can beenhanced. As a result, the quality of the endoscope image can beimproved. Moreover, since the endoscope image is calibrated in its coloraberration and distortion on the calibration table 16, the quality ofthe endoscope image can be more enhanced.

[0038]FIG. 3 is a schematic view showing the entire structure of anotherbody cavity-observing apparatus according to the present invention.Compared with the body cavity-observing apparatus shown in FIG. 1, thebody cavity-observing apparatus has only one wedge prism. Therefore, theactuator is modified so as to adapt to the one wedge prism. The otherparts are similar to the ones in FIG. 1, so that the same referencecharacters are given to the ones.

[0039] In the body cavity-observing apparatus shown in FIG. 3, the onlyone wedge prism 4 is attached to the forefront of the not shown imagingoptical system provided at the left edge of the rigid endoscope 1 sothat the right-handed surface is perpendicular to the optical axis. Theabove-mentioned actuator is constructed of an outer tube 21 movablyprovided on the periphery of the rigid endoscope 1, a joining shaft 23to join the wedge prism 4 and the outer tube 21 via a rotation shaft 22,a pulley 24 joined with the forefront of the rotation shaft 22, a belt25 associated with the pulley 24, a pulley 26 provided on the outer tube21, a first motor 28 having a rotation shaft 27 joined with the pulley26, and a second motor 31 having a gear 29 joined via a rotation shaft30.

[0040] Then, another rotation shaft 22, another joining shaft 23 andanother pulley 24 are provided on the back side of the bodycavity-observing apparatus so as to oppose the rotation shaft 22, thejoining shaft 23 and the pulley 24 which are provided on the front sidethereof. That is, the wedge prism 4 is sandwiched by the pair ofrotation shafts 22, the pair of joining shafts 23 and the pair ofpulleys 24.

[0041] Next, the scope controlling operation using the above bodycavity-observing apparatus shown in FIG. 3 will be describedhereinafter.

[0042] When a command signal to follow an object to be observed inputinto the scope controlling part 13 from the operating interface 12, thedriving amounts of the motors 28 and 31 are determined by the scopecontrolling part 13, to drive the motors 28 and 31 by the determineddriving amounts. Then, the wedge prism 4 is rotated in the directiondesignated by the arrow C around the optical axis X by the motor 31 viathe rotation shaft 30, the gear 29, the outer tube 21, the joined shaft23 and the rotation shaft 22.

[0043] At the same time, the wedge prism 4 is rotated by a given anglein the direction designated by the arrow D around the rotation shaft 22by the motor 28 via the rotation shaft 27, the pulley 26, the belt 25and the pulley 24. As a result, the prism 4 is moved at its differentposition from its starting position.

[0044] In the body cavity-observing apparatus shown in FIG. 3, the onlyone wedge prism is rotated in the arrow C direction and tilted in thearrow D direction, instead of independently rotating the wedge prisms 3and 4 as mentioned in FIG. 1. Therefore, in this case, a differentendoscope image can be obtained from the movement of the wedge prism 4.As a result, under a surgical operation, the working property can bedeveloped and the forefront of the endoscope can not be made an approachto an internal organ more than necessary. Moreover, the resolution ofthe endoscope image can be enhanced.

[0045] In this case, the endoscope image can be also calibrated in itscolor aberration and distortion on the calibration table 16.

[0046]FIG. 4 is a schematic view showing the entire structure of stillanother body cavity-observing apparatus according to the presentinvention.

[0047] Compared with the body cavity-observing apparatus shown in FIG.3, a liquid prism is employed instead of the wedge prism, and anactuator to move the liquid prism backward and forward along the opticalaxis X is provided. The other parts are similar to the ones in FIG. 3,so that the same reference characters are given to the ones.

[0048] In the body cavity-observing apparatus shown FIG. 4, the liquidprism 41 is attached to the forefront of the not shown imaging opticalsystem provided at the left edge of the rigid endoscope 1 so that theright-handed surface is perpendicular to the optical axis X. Theactuator is constructed of a first and a second link mechanisms 42 and43 which adjust the tilt angles for the Y axis and the Z axis orthogonalto the X axis.

[0049] The link mechanisms 42 and 43 have pairs of link shafts 44composed of planer portions 44 a joined with the periphery of the liquidprism 41 and orthogonal portions 44 b orthogonally followed by theplaner portions 44 a, link members 45 to support the orthogonal portions44 b of the link shafts 44, and motors 46 to rotate the link members 45around the Y axis and Z axis, respectively. The link members 45 havetheir elongated holes 45 a, respectively, and the link shafts 44 aremoved backward and forward by slipping the orthogonal portions 44 b inthe elongated holes 45 a through the rotation of the link members 45 bythe motors 46. Then, rotary encoders 47 to count the rotation numbers ofthe motors 46 are attached on the motors 46, respectively.

[0050] Next, the scope controlling operation using the bodycavity-observing apparatus shown in FIG. 4 will be describedhereinafter.

[0051] When a command signal to follow an object to be observed inputinto the scope controlling part 13 from the operating interface 12, thedriving amounts of the motors 46 are determined by the scope controllingpart 13, to drive the motors 46 by the determined driving amounts. Then,the link mechanisms 42 and 43 are moved backward and forward along the Xaxis by the motors 46, to move the liquid prism 41 backward and forwardin the directions designated by the arrows E and F shown in FIG. 4.Therefore, the forefront surface (left-handed surface) of the liquidprism 41 is tilted by a given angle. As a result, the liquid prism 41 ismoved at its different position from its starting position without themechanical movement or bending of the rigid endoscope.

[0052] In the body cavity-observing apparatus shown in FIG. 4, the onlyone liquid prism 41 is moved backward and forward in the arrows E and Fdirections, instead of rotating in the arrow C direction around theoptical axis X and tilting in the arrow D direction the only one wedgeprism 4 as mentioned in FIG. 3. Therefore, in this case, a differentendoscope image can be obtained from the forward and backward movementof the liquid prism 41. As a result, under a surgical operation, theworking property can be developed and the forefront of the endoscope cannot be made an approach to an internal organ more than necessary.Moreover, the resolution of the endoscope image can be enhanced.

[0053] In this case, the endoscope image can be also calibrated in itscolor aberration and distortion on the calibration table 16.

[0054] As is apparent from the above description, since a differentendoscope image can be easily obtained by slightly driving the wedgeprism or the liquid prism movably mounted on the forefront of the rigidendoscope as an endoscope, a wide range endoscope image can be easilyobtained and the body cavity-observing apparatus can be miniaturized.Moreover, due to the slight movement of the prism, the forefront of therigid endoscope can not be made an approach to an internal organ morethan necessary even though the actuator is operated mistakenly.

[0055] If a zoom mechanism is mounted on the above body cavity-observingapparatus, the magnification and reduction of the endoscope image can bealso carried out by a given optical system for the zoom mechanism, inaddition to the above-mentioned optical system such as the rigidendoscope and the prism to obtain a different endoscope image and thus awide range endoscope image. Therefore, since the body cavity-observingapparatus does not require the mechanical bending or the mechanicalmovement, the working property or the safety of not making an approachto an internal organ more than necessary can be developed under asurgical operation.

[0056] Although the present invention was described in detail withreference to the above example, this invention is not limited to theabove disclosure and every kind of variation and modification may bemade without departing from the scope of the present invention.

What is claimed is:
 1. A body cavity-observing apparatus comprising anendoscope with an imaging optical system on the front edge thereof, aprism movably mounted on the forefront of the imaging optical system,and an actuator to drive the prism on a given command signal, whereby adifferent endoscope image is obtained through the movement of the prism.2. A body cavity-observing apparatus as defined in claim 1, wherein theprism includes a first and a second wedged prisms having the samevertical angle which are provided closely and of which their adjacentopposite surfaces are orthogonal to the optical axis of the wedgeprisms, and the actuator includes a first and a second outer tubes whichare attached independently movably to the first and the second wedgeprisms and a first and a second motors to rotate the first and thesecond wedge prisms around the optical axis, respectively, whereby thedifferent endoscope image is obtained through the independent rotationsof the wedge prisms.
 3. A body cavity-observing apparatus as defined inclaim 1, wherein the prism includes one wedge prism, and the actuatorincludes an outer tube movably provided on the periphery of theendoscope, a joining shaft to join the wedge prism and the outer tube, afirst motor to tilt the wedge prism for the optical axis via the joiningshaft and a second motor to rotate the wedge prism around the opticalaxis through the rotation of the outer tube, whereby the differentendoscope image is obtained through the rotation and tilt of the onewedge prism.
 4. A body cavity-observing apparatus as defined in claim 1,wherein the prism includes a liquid prism, and the actuator includes afirst and a second link mechanisms which adjust the tilt angles for twodirections orthogonal to the optical axis, respectively, the first andthe second link mechanisms comprising pairs of link shafts composed ofplaner portions joined with the periphery of the liquid prism andorthogonal portions orthogonally followed by the planer portions, linkmembers to support the orthogonal portions of the link shafts, andmotors to rotate the link members, whereby the different endoscope imageis obtained through the backward and forward movement of the liquidprism.
 5. A body cavity-observing apparatus as defined in claim 4,wherein the link members have their elongated holes, respectively, andthe link shafts are moved backward and forward by slipping theorthogonal portions in the elongated holes through the rotation of thelink members by the motors.
 6. A body cavity-observing apparatus asdefined in any one of claims 1-5, further comprising aposition-detecting means to detect the position of the prism, whereby anendoscope image is calibrated in its color aberration or distortion onthe basis of the prism position information.